Speedometer Doesn't Reset

Hi Everyone,
I rode this morning and everything was fine. Later in the afternoon I rode and the speedometer needle started going up and down while I was going at a steady speed. All the other gauges seem to be fine. Now it doesn't reset from stop to stop. I winds up to about 160 and then back to zero. I have checked the speed sensor and it looked fine and was not loose or dirty (the bike has less then 4000 miles) I checked everything I could think of for loose connections
and found everything tight. A new speedometer is $650 plus and on e-bay they
are about $400 new. I don't want to spend that if I don't have to.
Anyone got any ideas? Because it doesn't reset am I out of luck? One more thing. I tried to reset the meter per the service manual but it made no difference. Thanks for any help.